Cat scan - radiation levels?

[Sarahsue1]

Hi Mumsnet, wondering if there are any radiographers out there who can help - I recently had a fall on holiday in Spain and local hospital gave me a cat scan. I didn't know until I returned home how dangerous they are?! I have the scans with the readings but have no idea what they mean - what levels I was exposed to. Lady passed me through the machine twice as I breathed on the beep the first time and I wasn't made to wear anything protective over eyes etc, not sure if this is ok. Have had a bad headache since but not sure if this is coincidence! Any advice / insight much appreciated

Life is hazardous, no matter what you do.
Sarahshoe, why did you have the CAT scan? What would have happened to you if you didn't get it.

am a bit worried that the regulation in Spain may be different to the UK because my scan readings are showing different measurements AND they put me through the stupid machine twice aaaaargh

Are you somehow suggesting that in Spain, they give people CAT scans with radiation doses high enough to damage them? Why would they do that?
Why are people so dense?

In brief, no x-ray machine (including CT scanner) can give you the value in mSv. This value is calculated using information from both the equipment and the person being scanned, and also takes into account how sensitive the different organs and tissues are to ionising radiation. The brain is not very sensitive so the effective dose and therefore risk from a CT scan to the brain is relatively low. I hope this helps a bit, I could explain in much more detail but I really feel that it might not be helpful to you.

It is very true that we don't actually know what the relationship between ionising radiation and detrimental effects at low doses is, because we only have data from high dose exposures to go on (e.g Hiroshima/Nagasaki victims, Chernobyl clean up workers). But we assume that a small amount of radiation may increase the risk of these effects as a worst case scenario, to enable us to protect patients undergoing medical exposures, and the staff who work with ionising radiation every day

CremeFresh Yes blueberrys, and bananas are radioactive as is venison

@ragged I fell from a balcony. I don't know what would have happened if I didn't have it - I was pretty out of it. True everything is risky but there are some very negative statistics surrounding cat scans that I didn't know about. It's done now but I am just annoyed and I want to know why the measurements they have used are not the same as cat scans i have seen online - am going to ask them! That was the reason for my post, to try and find out if any radiologists would have any insight. Will see what the hospital say

Thanks @wheredoallthepokemongo, very helpful this is another thing I don't understand though (sorry, totally ignorant about these things - OBVIOUSLY!) when the beams or whatever they are pass through to get to skull isn't there also a risk to surrounding tissues so eyes and skin - aren't they exposed then to radiation to?

Op, with the greatest respect I am going to hand you a grip.
Radiographers and physicists have answered your query , stating not to worry you have had the scan .
In light of this expert info you seem determined to find a problem .
I'm not entirely convinced your bump to the head hasn't caused an issue .🙂

I don't know what would have happened if I didn't have it - I was pretty out of it.

They would have been ruling out a bleed in your brain-potentially fatal. The risk of long term harm from the scan is minuscule. The immediate risk to you from an undiagnosed haemorrhage was much much greater.

@hotbot - I need a grip, no offence taken - a close family friend has terminal cancer at the moment and previously had cat scans so I am not in the greatest headspace, in every sense of the word as well as the fall. But I guess what's done is done and am thankful I didn't have an actual serious brain injury - just my bizarre worry tendencies which have been there before the fall

🙂🍰🍷🌷🌷🌷🌷

I don't believe any of the numbers on those pictures corresponds to any sort of radiation dose - I can see date, time and what looks to be a patient id number.

a close family friend has terminal cancer at the moment and previously had cat scan

My father has terminal cancer and also drinks coffee, but I'm not jumping to conclusions that coffee causes cancer.
You're being very silly and irrational.

DH who works in a office full of nuclear physicist's. After studying the wildlife at Chernobyl a little bit of radiation is good for you. A lot is bad.

There are no measurements shown on your scans - IMA is the image number, SP is the slice position and a MIP (maximum intensity projection) is a 3D reconstruction of multiple 2D images. As others have said, the radiation dose involved in a CT scan of the head is low, and there is absolutely no need for eye protection etc. There is always a risk involved when having scans which use ionising radiation, but generally speaking, the risk increases as the dose increases, so as the dose in your scan was tiny then the risk is also tiny! Doctors have to weigh up the risks vs the benefits before giving anyone a CT scan, and the benefits of checking for bleeds etc vastly outweigh the risks from the radiation. In terms of cumulative effects, you would need to have many, many more CT scans before this became an issue. Please don't waste any more time worrying about this!

Just read the extracts from the articles you posted - not sure if this helps but my understanding is as follows: there are two types of effects caused by exposure to radiation - "deterministic" and "stochastic". Deterministic effects are things like burns to skin, damage to the eyes etc, and for each effect there is a threshold dose that has to be exceeded before the effect occurs, and the severity of the effect increases as the dose increases. The main stochastic effect is cancer - there is no threshold dose (so basically it can happen with any dose of radiation, and there is no such thing as a "safe" dose) and the likelihood of the effect increases with increasing dose. So yes, there is a theoretical risk of cancer from a CT scan, but the likelihood of this actually happening is vanishingly small, and the dose used is well below the threshold for determinist effects so these are not a concern. All CT scans are performed such that the dose is as low as it can possibly be while still allowing diagnostic-quality images to be obtained. Possibly too much information here, but hopefully it answers some of your questions

@Sarahsue, I think @Elvander has given you a really comprehensive response regarding radiation and the associated risks. Just wanted to say that I'm sorry to hear about your relative; please remember that although people are quick to talk about the risks of CT scans, they don't talk about the many, many benefits which include diagnosis of a range of issues, many of which are emergent. For example, my father had a stroke which was quickly confirmed by CT and he had treatment within the golden 3 hours, meaning chances for a much better outcome were maximised.

Please move forward with your recovery now and try not to think anything more of it

Whoever arranged or authorised your CAT scan was doing their best to make sure you got any care you needed. If you had a brain injury then delayed treatment could have meant your death. It was a necessary test.

What's done is done. Worrying about this will be a total waste of your time & energy. Your choice.

As radiographers , we have to justify every X-ray and scan. If we think it's not necessary we can reject the request, quite often if there is any doubt regarding the necessity of a scan we will run it by a consultant radiologist. We really don't scan people just for the hell of it.

Thanks @ragged - have now stopped googling!

Late to the party but hello Pokemon. I probably know you in real life.

Please stop calling them cat scans. They haven't been that for about 20 years. Say CT!

Also pp, radiographers cannot ever, ever justify CT scans. Unless you work somewhere remarkably 'free' from IRMER. You might be authorising under protocol however. Ahem. I'll get my coat.